Measuring the shear force of lamb meat cooked from frozen samples: comparison of two laboratories

Abstract

The tenderness of 160 samples of m. longissimus thoracis et lumborum (LL) from 40 sheep carcasses was measured at two laboratories, 80 samples per laboratory, with two ageing times (0 and 5 days). The samples were all cooked from frozen and then measured on the same type of machine, a Lloyd Texture analyser with a Warner–Bratzler-type shearing blade attached to give a shear force value for each sample. Shear force results were natural log-transformed and the analysis showed that there was a significant (P < 0.001) effect of ageing on shear force and a significant (P = 0.01) difference between the laboratories. Thus, on equivalent samples, Laboratory B produced shear force results 0.78 times those for Laboratory A. There was no significant (P > 0.05) effect of ageing on cooking loss, but there was a significant (P < 0.05) difference between the laboratories. On equivalent samples, Laboratory B produced lower cooking loss results (expressed as a percentage), on average by 3.1%, than did Laboratory A. When cooking loss was included in the model for shear force, it was significant (P < 0.001), and its inclusion reduced the significance (P = 0.04) of the difference between laboratories. Thus, part of the differences between the two laboratories for shear force could be explained by the difference in the cooking loss at the two laboratories. As cooking loss increased, shear force increased.